Import code from previous AssetBuilder version

thirdparty/libsquish/rangefit.cpp

@@ -0,0 +1,201 @@
+/* -----------------------------------------------------------------------------
+
+    Copyright (c) 2006 Simon Brown                          si@sjbrown.co.uk
+
+    Permission is hereby granted, free of charge, to any person obtaining
+    a copy of this software and associated documentation files (the
+    "Software"), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sublicense, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+   -------------------------------------------------------------------------- */
+
+#include "rangefit.h"
+#include "colourset.h"
+#include "colourblock.h"
+#include <cfloat>
+
+namespace squish {
+
+RangeFit::RangeFit( ColourSet const* colours, int flags, float* metric )
+  : ColourFit( colours, flags )
+{
+    // initialise the metric (old perceptual = 0.2126f, 0.7152f, 0.0722f)
+    if( metric )
+        m_metric = Vec3( metric[0], metric[1], metric[2] );
+    else
+        m_metric = Vec3( 1.0f );
+
+    // initialise the best error
+    m_besterror = FLT_MAX;
+
+    // cache some values
+    int const count = m_colours->GetCount();
+    Vec3 const* values = m_colours->GetPoints();
+    float const* weights = m_colours->GetWeights();
+
+    // get the covariance matrix
+    Sym3x3 covariance = ComputeWeightedCovariance( count, values, weights );
+
+    // compute the principle component
+    Vec3 principle = ComputePrincipleComponent( covariance );
+
+    // get the min and max range as the codebook endpoints
+    Vec3 start( 0.0f );
+    Vec3 end( 0.0f );
+    if( count > 0 )
+    {
+        float min, max;
+
+        // compute the range
+        start = end = values[0];
+        min = max = Dot( values[0], principle );
+        for( int i = 1; i < count; ++i )
+        {
+            float val = Dot( values[i], principle );
+            if( val < min )
+            {
+                start = values[i];
+                min = val;
+            }
+            else if( val > max )
+            {
+                end = values[i];
+                max = val;
+            }
+        }
+    }
+
+    // clamp the output to [0, 1]
+    Vec3 const one( 1.0f );
+    Vec3 const zero( 0.0f );
+    start = Min( one, Max( zero, start ) );
+    end = Min( one, Max( zero, end ) );
+
+    // clamp to the grid and save
+    Vec3 const grid( 31.0f, 63.0f, 31.0f );
+    Vec3 const gridrcp( 1.0f/31.0f, 1.0f/63.0f, 1.0f/31.0f );
+    Vec3 const half( 0.5f );
+    m_start = Truncate( grid*start + half )*gridrcp;
+    m_end = Truncate( grid*end + half )*gridrcp;
+}
+
+void RangeFit::Compress3( void* block )
+{
+    // cache some values
+    int const count = m_colours->GetCount();
+    Vec3 const* values = m_colours->GetPoints();
+
+    // create a codebook
+    Vec3 codes[3];
+    codes[0] = m_start;
+    codes[1] = m_end;
+    codes[2] = 0.5f*m_start + 0.5f*m_end;
+
+    // match each point to the closest code
+    u8 closest[16];
+    float error = 0.0f;
+    for( int i = 0; i < count; ++i )
+    {
+        // find the closest code
+        float dist = FLT_MAX;
+        int idx = 0;
+        for( int j = 0; j < 3; ++j )
+        {
+            float d = LengthSquared( m_metric*( values[i] - codes[j] ) );
+            if( d < dist )
+            {
+                dist = d;
+                idx = j;
+            }
+        }
+
+        // save the index
+        closest[i] = ( u8 )idx;
+
+        // accumulate the error
+        error += dist;
+    }
+
+    // save this scheme if it wins
+    if( error < m_besterror )
+    {
+        // remap the indices
+        u8 indices[16];
+        m_colours->RemapIndices( closest, indices );
+
+        // save the block
+        WriteColourBlock3( m_start, m_end, indices, block );
+
+        // save the error
+        m_besterror = error;
+    }
+}
+
+void RangeFit::Compress4( void* block )
+{
+    // cache some values
+    int const count = m_colours->GetCount();
+    Vec3 const* values = m_colours->GetPoints();
+
+    // create a codebook
+    Vec3 codes[4];
+    codes[0] = m_start;
+    codes[1] = m_end;
+    codes[2] = ( 2.0f/3.0f )*m_start + ( 1.0f/3.0f )*m_end;
+    codes[3] = ( 1.0f/3.0f )*m_start + ( 2.0f/3.0f )*m_end;
+
+    // match each point to the closest code
+    u8 closest[16];
+    float error = 0.0f;
+    for( int i = 0; i < count; ++i )
+    {
+        // find the closest code
+        float dist = FLT_MAX;
+        int idx = 0;
+        for( int j = 0; j < 4; ++j )
+        {
+            float d = LengthSquared( m_metric*( values[i] - codes[j] ) );
+            if( d < dist )
+            {
+                dist = d;
+                idx = j;
+            }
+        }
+
+        // save the index
+        closest[i] = ( u8 )idx;
+
+        // accumulate the error
+        error += dist;
+    }
+
+    // save this scheme if it wins
+    if( error < m_besterror )
+    {
+        // remap the indices
+        u8 indices[16];
+        m_colours->RemapIndices( closest, indices );
+
+        // save the block
+        WriteColourBlock4( m_start, m_end, indices, block );
+
+        // save the error
+        m_besterror = error;
+    }
+}
+
+} // namespace squish